Crosslinked polyethylene tubing (PEX) is widely used in plumbing applications for transporting potable water. In such systems, connections are typically made using fittings that are crimped in place by a crimp tool. Most fitting systems are radial press systems. A seal is created by inwardly compressing the PEX tubing over a barbed male component or other component such as a union, T-adapter, manifold, or valve. A ring or sleeve is positioned over the tubing and permanently deformed around the entire circumference of the tubing using the crimp tool to create a compressive seal between the tubing and the component. Thus, the crimp tool engages the ring radially and the crimp profile formed in the ring results from the tool. An example of these systems are those that satisfy the ASTM F1807 crimp standard.
Although satisfactory in many respects, crimped connections may exhibit dimensional variations in the circumferential crimped regions or bands formed in the ring or sleeve. In many instances, an axial variability may exist in which one portion of a crimped region is not aligned or “matched” with an adjacent portion of the crimped region. Thus, one portion of the crimped region may appear to be axially “shifted” relative to its adjacent portion.
Another dimensional variation that may exist in a crimped connection is in the diameter of the crimped region. In particular, diametric dimension repeatability may be poor from one crimp to another crimp.
Both of these problems, i.e., axial variability of crimps and diametric dimension repeatability between crimps, can result from poor axial alignment between the dies of the crimp tool. Accordingly, a need exists for methods and provisions to axially align dies and thereby reduce the potential for occurrence of the noted problems.